Among the more promising organic insecticides developed as substitutes for lead and arsenic is phenothiazine. When field tests were made on the practical application of this insecticide for control of the codling moth, some of the men applying a spray containing the compound complained later of intense itching, irritation and reddening of the skin. In some cases the reactions were severe, being accompanied by edema and secondary infection in areas of intense hyperemia, and required hospitalization. Attending physicians have diagnosed the reaction variously as sunburn, chemical burn and dermatitis.

In sharp contrast to these reports is the fact that several members of our laboratory staff have worked with phenothiazine for several years on an investigation of its toxicity and have experienced no cutaneous reactions. Applications to the forearms of phenothiazine mixed with hydrous wool fat to promote absorption produced no irritation. In an investigation of the efficacy of phenothiazine as